373
FXUS64 KSHV 091216
AFDSHV
Area Forecast Discussion
National Weather Service Shreveport LA
616 AM CST Fri Dec 9 2016
.AVIATION...
For the ArkLaTex, SKC making for a chilly start. Looks like a bit
of cirrus is on approach, otherwise just a shift in the sfc winds
as the center of the 1040mb arctic high in MO cross the MS river
later today. Sfc winds are expected to remain less than 10 KTS
with N attm, becoming NE/E and slacking to SE by sundown. Aloft,
we are light N 10-20KTS up to 10kft then back to West and run
35-70KTS on up into flight levels. Near repeat tomorrow early and
then warmer with clouds increasing. SHRA expected in on Sunday.
/24/
&&
.PREV DISCUSSION... /issued 456 AM CST Fri Dec 9 2016/
DISCUSSION...
Arctic air continues to spill S into the region this morning...although
N winds 5-10kts have slowed the temp fall despite a clear sky in
place. The arctic sfc ridge over Ern OK/Wrn AR will continue to slide
slowly E into the MS Valley by this evening...with the weak cold
advection expected to maintain much below temps areawide this
afternoon. Have been watching the extensive 7-8kft cigs over Ncntrl
TX...which have begun advancing E and approaching Ecntrl TX
attm...with the WRF suggesting these cigs affecting portions of E TX
along/S of I-20 later this morning before eventually slowly eroding
during the day. Not quite sure how fast or if these cigs will
completely erode...but it/s possible that this cloud cover may also
impede warming today over portions of E TX...but for now...have
trended max temps near MOS. Don/t think the cloud cover will be a
factor tonight except over portions of E TX/SE OK...with light ESE
winds resulting in good radiational cooling conditions overnight.
Have trended min temps a bit colder than the previous
forecast/MOS...with the coldest temps over SW AR/Ncntrl LA as a
prolonged freeze is expected.
Leeside troughing over the Cntrl/Srn Plains Saturday will result in a
tightening pressure gradient over these areas...resulting in a rapid
increase in low level moisture which will begin advancing into E TX/SE
OK by afternoon...and over the remainder of the region during the
evening. A 45-50kt Swrly LLJ will enhance H850 theta-e ridging over
the region Saturday night...which may result in isolated to widely
scattered areas of -RA/-DZ...possibly expanding in coverage Sunday
with the approach of a weak shortwave that will enter the Red River
Valley over Srn Ok/N TX Sunday afternoon. Moisture will remain limited
ahead of this shortwave...with any rainfall amounts expected to be
light. Should also see a marked increase in temps/dewpoints as
well...with above normal temps returning Sunday afternoon under gusty
Srly winds. The aforementioned shortwave will help drive a weak cold
front SE into the area Sunday night...which may eventually stall
somewhere over E TX/N LA Monday /per the ECMWF/. Still could see
isolated to sct -SHRA develop ahead of the front...but drier air
entraining E on the WSW H850-500 winds should help to limit the extent
of development before the shortwave departs the area Monday morning.
This bndry may actually begin to shift back SE Tuesday...as another
wedge of colder arctic air begins to build back S ahead of sfc ridging
building back S into the Srn Plains/Lower MS Valley. Did maintain
slight chance pops with the passage of this next frontal system...with
a return to below normal temps expected for the mid/late week
timeframe. This next cold snap should be brief though...with a Serly
low level flow returning Thursday night resulting in a modification in
temps Friday through next weekend. A zonal flow aloft over the Srn
Plains through this period looks to become more SW by late
weekend...which could eventually return wet conditions just beyond the end
of the extended.
Prelims to follow below...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 45 27 51 43 / 0 0 0 20
MLU 44 24 51 38 / 0 0 0 10
DEQ 42 24 47 39 / 0 0 0 30
TXK 43 25 48 42 / 0 0 0 20
ELD 42 22 49 38 / 0 0 0 10
TYR 45 29 50 45 / 0 0 0 30
GGG 45 27 51 44 / 0 0 0 30
LFK 47 28 55 47 / 0 0 0 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
24/15